I just thought I'd do a round-up post of the setup here so anybody starting out can see what (in some situations) can work well. I remember feeling very confused when first starting to breed chickens about exactly how many pens and cages I would need.
There would be many improvements I could make, namely in terms of handling parasitical worms organically (i.e. more land to pen-rotate), but this is what I've got, and it's working well.
1. Incubator or broody hen. I know, obvious...
2. Brooder tub with lamp for chicks drying off and getting started (day 1-2). I use the largest tub I could find and it holds up to 50 day olds in the laundry with a single 40 or 60W infra red globe (depending on ambient temperature). I find with infra red lamps the tub can gradually overheat, so it's vital to keep checking. During this time I add probiotics and a tiny amount of healthy adult droppings to their food/environment. Slow exposure to coccidiosis seems to work best started at day 1 and including a range of protections such as soured milk.
3. Larger brooder for 2 days old to 3 weeks. I use either a cold brooder (see other posts) or a lamp. This brooder is also seeded with a small amount of adult hen droppings to make sure cocci exposure happens early. At 3 weeks artificially raised chicks start shedding high numbers of cocci oocysts and need to be moved so the brooder doesn't get 'seeded' with massive numbers that could harm the next chick batch. I have 3 brooders but only use one at a time, depending on how many chicks I have and how much work I want to do.
4. Tractor for 3 weeks to 10 weeks. During this time I shift the tractor regularly to keep the birds on grass and limit exposure to cocci. However I gradually slow this down, i.e. after 1 week on the ground I shift the tractor only every 2nd day, and after that every 3rd, 4th, etc. If grass disappears I always move them no matter what, even if it's a day. This tractor is nearly 4m x 2.7m so it's a good size.
5. Grower pen for 10 weeks to 16 weeks. During this time I select future breeders. The birds have usually become cocci immune before arriving in this pen.
6. Adult pens x 2, both with separate access to a sound-reducing night-shed (divided down the middle). This means I can keep 2 separate breeder flocks.
7. Broody hen pens x 2. These are sheds with mesh fronts that are used when a hen wants to raise chickens. I have a small ratproof one and a larger non-ratproof one. At 3 weeks the hen and babies are moved to either the tractor (if it's free) or the larger shed. I wouldn't need these if I was happy to artificially raise chicks all the time, but I often prefer leaving it to the hens.
8. Quarantine cage. I also use this cage as an overnight cage for the odd table cockerel to be processed early next day. It's a 1m square (approx.) mesh cage that I can take anywhere, e.g. onto grass if I'm wanting to use it as a temporary tractor. However it tends to stay empty unless I acquire a new rooster and want to make sure he's healthy.
I guess that's quite a lot of pens and cages, however it's not a huge setup in itself. But it works for me.